1. Field of the Invention
The present invention relates to via patterns of a double patterning mask set, and more particularly, to via patterns of a double patterning mask set having truncated corners.
2. Description of the Prior Art
Mask design is a necessary and important step during design and manufacturing processes of an integrated circuit. In the step of mask design, a corresponding via pattern array is generated according to circuit design of the integrated circuit. The via pattern array is then formed on a mask for exposing a wafer in the manufacturing processes of the integrated circuit. However, scale of the manufacturing processes of the integrated circuit is getting smaller, and wavelength of light of current exposure machines is limited, so if the via patterns on the mask are too close to each other, the patterns developed on the wafer may be incorrect due to light interference, such that the integrated circuit fails.